Evaluation of antinociceptive and anti-inflammatory activities of standardised rootbark extract of Xeromphis nilotica.

ETHNOPHARMACOLOGICAL RELEVANCE: Xeromphis nilotica (Stapf) Keay (Rubiaceae), popularly known as 'barbaji' (in Nigeria), is a lowland shrub that grows wild in tropical areas of Africa and Asia. The plant׳s extract is used for the treatment of various diseases in folk medicine including pain related ailments. Important bioactive constituents have been isolated from the plant among them are coumarin, alkaloids, flavonoids, saponins, and terpenes. This study is aimed to evaluate the analgesic and anti-inflammatory efficacy of standardised aqueous extract of the plant using in vivo models of pain and inflammation in mice and rats. MATERIALS AND METHODS: Aqueous extract of Xeromphis nilotica root bark was prepared and standardised using HPLC technique. Three dose levels (25, 100 and 400mg/kg) of the extract were used, administered orally to laboratory mice and rats. Acetylsalicylic acid (100mg/kg, p.o.) was used as the positive control. Nociception was induced in laboratory rodents: chemically using acetic acid and formalin, and mechanically using analgesy meter; while inflammation was induced using fresh raw egg albumin. RESULTS: The extract showed 11 constituents peak profiles in the HPLC analysis. The extract alleviates mice response to acetic acid-induced writhing, analgesy-meter and formalin tests. It significantly decreased the oedema induced by egg albumin induced inflammation, but failed to show significant effect beyond 80min of the test. CONCLUSION: The extract has antinociceptive effect and short acting anti-inflammatory activities. The results justify its usage in the treatment of pain and inflammatory conditions, and also provided evidence of its potential as source of new pain relief drug prototype.

Neuropharmacological effects of standardized aqueous stem bark extract of Parkia biglobossa in Wistar rats.

OBJECTIVE: Parkia biglobossa stem bark decoction is a popular medicinal plant preparation used as calming agent for tensed patients in traditional medicine. The aim of this study was to evaluate the effects of aqueous stem bark extract of Parkia biglobossa (AEPB) and its active fraction AEPBF3 on anxiety, spontaneous alternation behavior, and locomotor activity. The open field apparatus was used to evaluate effects of AEPB and AEPBF3 on locomotion. The APBE and the active fraction AEPBF3 were standardized using reverse phase high performance liquid chromatography to establish finger print to ascertain identity and stability of the extracts over time. MATERIALS AND METHODS: The oral median lethal doses (LD50) of AEPB and AEPBF3 were evaluated using modified Lorke's method in rats. The effect of APBE (50-200 mg/kg p.o.), APBEF3 (25 and 50 mg/kg p.o.), diazepam (2.5 mg/kg, i.p.), and 10 ml normal saline/kg on anxiety-like behavior, spontaneous alternation behavior, and locomotion activity were evaluated in rats on elevated plus maze (EPM), Zero-maze, Y-maze, and open field apparatus, respectively. The oral LD50 values of AEPB and AEPBF3 were estimated to be 5000 mg/kg and 3800 mg/kg body weight in rats, respectively. RESULTS: AEPB and AEPBF3 significantly (F6, 41=2342, p<0.0001) increased time spent in the open arm of EPM and significantly (F6, 41=2323, p<0.0001) increased time spent in open arms of the Zero maze. The AEPB and AEPBF3 administration produced significant increase (F5, 35=154, p<0.0001) in spontaneous alternation behavior in rats. The AEPB extract and its fraction AEPBF3 significantly increased total locomotor activity (F6, 41=413, p<0.0001) and rearing (F6, 41=150, p<0.0001) in the open field apparatus. CONCLUSION: The results of the present study provided evidence for anxiolytic and nootropic effects of the AEPB and AEPBF3, thus providing scientific basis for its continuous use in the management of neuropsychiatric disorders characterized by apprehension and amnesia.